ACSM file not loading completely

Downloading acsm files from bibl.onleihe.de successful.

Opening this file by Adobe Digital Editions 2.0 will start, but not finish loading the file. Digital Editions hangs and must be killed.

This problem occurs, since I hat updated to Mac OS 10.11.4 (El Capitan).

In the forum I found some similar questions - but no answer.

Where is Adobe?????!!!!!!!